The prevalence of sexually transmitted diseases (STD) and risky behaviour patterns were studied in 165 adolescents attending a STD clinic in Jamaica. A standardised structured questionnaire, clinical algorithms for STD and serological tests for HIV and syphilitic infection were applied. High prevalences of risky behaviour including young age at onset of sexual activity, especially in boys, (mean age 12.5 +/- 2.5 years); unprotected sexual intercourse (only 4% used condoms consistently); multiple sexual partners (mean 3.8 +/- 2.4 and 1.8 +/- 1.2 for boys and girls, respectively) were found. Marijuana, used by 60% of the boys, was an independent risk factor for dysuria (adjusted Odds Ratio (OR), 2.0; 95% CI, 1.6-3.4). Repeated episodes of STD (33%), coinfection with HIV (1.2%), syphilis (1.2%) and teenage pregnancy (13%) were prominent findings. Educational strategies which promote behaviour intervention at an early age, frequent and consistent use of condoms, abstinence or delayed onset of sexual activity are essential to reducing the HIV/AIDS and STD risk in adolescents in Jamaica.....read more